Electrochemical characteristics of amorphous MgTi x Ni (x = 0, 0.1, and 0.2) hydrogen storage alloys

Abstract

MgTi x Ni (x = 0, 0.1, and 0.2) alloys were successfully prepared by mechanical alloying (MA), and the influence of milling time on the electrochemical characteristics of the electrodes was discussed. MgTi x Ni alloys after 90 h milling displayed the best electrochemical performance. The X-ray diffraction patterns showed that the alloy ball-milled for 90 h was amorphous with a widened diffraction peak. The charge-discharge tests indicated that these alloys had good electrochemical activation properties, and the MgTi 0.2 Ni alloy electrode exhibited the best cycle performance. The initial discharge capacity of the MgTi 0.2 Ni alloy reached up to 401.1 mAh·g −1 , and the retention rate of capacity was 31.0% after 30 cycles, much higher than that of MgNi (17.3%). The Tafel polarization curves revealed that Ti addition could enhance the anticorrosion performance of these alloys in alkali solution, which was responsible for the ameliorated cyclic stability of these alloy electrodes.